Cryptographic attachment for typewriter keys



' Jan. 27, 1948. R. N. CUNNINGHAM 2,435,130

- CHYPTOGRAPHIC ATTACHMENT FOR T YPEWRITER KEYS Filed Oct. 5, 1944 1 2Sheei :s-Sheet 1 a 5 w i k Jan. 27, 1948. R. N. CUNNINGHAM 2,435,130

GRYPTOGRAPHIC A'r'mcaumr ron 'ryrxwm'rnn KEYS Filed Oct. 5, 1944 v 2Sheets-Sheet 2 RMCannz'ngfiam I Patented Jan. 27, 1948 CRYPTOGRAPHICATTACHIHEN'I' FOR TYPEWRITER KEYS mi; N. Cunningham, Washington, D. 0.

Application October 5, 1944, Serial No. 557,346

ZQlaims.

This invention relates to cryptograph systems and to a means foradapting an ordinary or standard typewriter keyboard to such system.

An object of this invention is to provide an attachment for the keys ofa typewriter in the Iorm 01 caps fitting over the present keys, the capsbeing in the form of removable code caps which are formed in such mannerthat the characters of the original keys are visible therethrough. Inone form of the invention the code caps are formed with a top wallhaving a central transparent window whereby the characters of theoriginal keys may be viewed therethrough, and in another form of theinvention the top wall of the cap is formed with a central opening forexposing to view the character of the key. In each form of cap thearrangement of the code characters is the same, such characters beingarranged circumferentially about the window.

The code system to be hereinafter described embodies four codes, eachone of which is identifled by a particular color and position on thecode cap. In the coding of a message any single series of codecharacters may be used, or the coded words or groups of characters mayembody two or more of the code series, and where two or more of the codeseries are used, the code series may be used in a prearranged sequence,and such sequence may also be varied for each coded group of characters,thereby forming a non-uniform code which will make it practicallyimpossible to decode without prior knowledge of code series sequencesused.

Another object oi. this invention is to provide an improved method offorming a code system which is capable of numerous variations orcombinations of codes so that an uniniormed decoder will be unable totranslate or break the code.

To the foregoing objects, and others which may hereinafter more fullyappear, the invention consists of the novel construction, combinationand arrangement of parts, as will be more specifically referred to andillustrated in the accompanying drawings, but it is to be understoodthat changes, variations, and modifications may be resorted to whichfall within the scope of the invention as claimed.

In the drawings:

Figure l is a diagrammatic view of a conventional typewriter keyboard,having a crypto- 2 7 graphic means mounted thereon in accordance withthis invention.

Figure 2 is an enlarged plan view ot a series or typewriter keys havingcryptographic caps mounted thereon.

Figure 3 is an exploded view showing in top plan the cryptographic captogether with the crimped holding ring for the conventional indiciaplate on the key.

Figure 4 is a sectional view taken on the line 4-4 of Figure 2.

Figure 5 is a top plan of a series of keys having mounted thereon amodified form of cryptographic attachment.

Figure 6 is a. sectional view taken on the line 6-6 of Figure 5.

Referring to the drawings, the numeral in des-- ignates generally aconventional keyboard for a typewriter, havin key bars ii formed withhead I2 on which a plate I3 is mounted bearing the indicia M. The plate13 is held on the top of the head i2 by means of a crimped ring-'5. Acap generally designated as it is mounted on the key, engaging about thering 15, and includes a top wall l'i, which is of concave configurationon the upper side and is provided with a cylindrical skirt l8 engagingabout the ring [5 and frictionally held thereon.

The top wall I! is preferably cf opaque material and is formed with a,centrally disposed transparent wall portion l9. The transparent wallportion i9 is provided so that the character l4 ot the key bar will bevisible through the cap l6. There is one cap l6 for each one of the keybars or keys.

In order to provide a means whereby the typewriter may be used for bothcoding and decoding a message, I have provided on the upper side of thetop wall I! about the window or transparent portion IS, a plurality ofcharacters 20, ii, 22 and 23. The characters 20 to 23 are alphabeticalcharacters, but are different from the character of the particular keybar. In arranging the several series of code characters, as hereindisclosed, there are four series of code characters with thealphabetical characters of each series scrambled so that there will notbe any definite sequence or relation of a code character to the normalalphabetical character on the key bar.

There is given below a tabulation, showing the CcdeSeriesNo.'1UQHYOPWCZMTNJLEFBSRKAXGVD 2FHLPGAEBNSVCUIXDYWJZMKROQ' E'3RVEOCXKUSYGPTWDLZAIMHBNFJQ 4 CPAFODSLWZTHVREBVNGKYQIMUJ .The followingis a simple form or use of the and the top wall ll is formed with anopening tation.

123412341 234123412 3412341 #1 KBCGDJMOJ BRGFWDQOP'DDXFPYO-4321432l4-32l432l43 2143214 #4-KUGRUIZOUUFRBAXXO0XPQRCAO I Where theseries of codes are usedtogether and A a -s m m 1 m t fact that insequence, the initial code word is preceded by a As an example, if thesequence is 1, 2, 3, 4, the

differentiation in the colors of the characters of ticular positions of'the code characters 20 to 23 four codeseries and their relation to thenormal alphabetical characters appearing on the key era;

In Figures 5 and 6 there is disclosed a slightly modified form of thisinvention, wherein the code caps l6 are formed with an opaque top walll1 ABCDEFGHIJKLMNOPQRSTUVWXYZ characters of eachvcode series. As anexample, 24 instead of a transparent window. The key the sentence,The-system has proved of value" bar character is visible throu h he 0 gis coded as follows for each of the four code g t pemng 24 in the samemanner as the key bar character is series. 7 visible through thetransparent window is of cap #1 KCORDRKOJ CURFSEXOY, EPXUNAO 5:25ggglagiggg It will be understood that while referenceis R made to thecode 5 st m mbod #4 KLOGUGKOV LCGBNEQOF- EDQCHYO y e e ymg four codesthat there might be a lesser or a. greater number than four, and it iscontemplated that the invention-shall be construed as being of suchscope. Likewise, where the term cap is used, it will be understood toinclude a ring or a, skirted annulus. the scope of the termrbeinsintended as a word of general designation and not a: a word of limi-Another method of using this code system is to use all four code seriesin the formation of the code words or characters, and thenseveral seriesmay be used in sequence. This sequence maybe either in the sequence ofthe numbered series such as l, 2, 3, 4, or the sequence maystart withany preselected series:

the typist can use the machine in the ordinary the numeral of the firstseries. of thesequence. manner with the standard keyboard and. if

sired, can switch at any pointin the message to code merely by'observingthe selected adjacent symbol. This is a great advantage in a device of40 this character. Furthermore, in decoding, the typist can easilyobserve the standard letters as well asthe selected code letters, noalteration of the keyboard or interference with the .normal use M 5 ofthe machine being required.

What I claim is:

1. As a new article of manufacture a cryptographic attachment comprisinga cap engageable over one key of a typewriter, said cap including a topwall having a centralformation through which the character of-said keywill be visible,

. a cylindrical skirt about said top wall engageable about: saidkey,-an'd circumferentially. spaced apart code indicia on theuppersurface of. said wall surrounding said central formation, said codeindicia denoting characters different from the character ofsaid keywhereby. a code character may be written or transcribed inaccordancewithany one of. a plurality of difierent code 0 systems by striking thekeyhbearingthe code indicia.

2. As a new article of manufacture a cryptocodewordis:

' fl KBGGD-JM-OJ Where the code series is in-reverse sequence, the codeword is also preceded by the numeral designating the first seriesstarting the word, such as #4 KUGRUIZOU As another example, the codeseries may be used alternately. such as series 2 and 4, or reversely 4and 2,- as indie ited below:

Where alternate code series are used, the first code word is preceded bythe two numerals designating the sequence of the code series. such as:

,- 24 ZLGGQGZ0J 42 LFGDNXQGF The above are only a few examples ofthemanher in which the code series may be used. In order to assist-incodinr: and decoding themessage, the characters 20 of the firstcOdeseries may be colored red; the characters of the second code seriesmay be colored blue; the characters of the third code series may becolored red; and graphic attachment comprising a cap engageable thecharacters of the fourth series may be colover -'a,:keyof a. typewriter,said cap including a cred black. It will. of course, be understood thattop wall having a: transparent central panel the characters on the capsthe coding and whereby-the character of said .kcy may be viewed, thedecoding machine Wm be identical, and the a cylindrical skirt aboutsaidtop wall engageahle at said ke and circumferentially spaced thedifferent code series is-designed to facilitate abo y both the codingand the decoding of the message. igg i' g'fi z gg fi gg g zggz zfg fg223:3

panel, said code indicia denoting characters different from thecharacter of said key whereby a nude charactermay .be written or,transcribed 7 in accordancewith any-one of a plurality of dif- However,if desired, the characters 20 to 23 may be all of the same color, andthe coding and decoding of the message is accomplished by the paron thesurface of the cap.

ve ul-ullm.

aegan ferent code systems by striking the key bearing Number the codelndlcia. 1,541,043 ROY N. CUNNINGHAM. 1,203,570 7 442,374 7 REFERENCESCITED 5 527,112 The following references are of record in the me of thispatent: )3351 7 1,718,694

UNITED STATES PATENTS Number Name Date m 1.093.372 Allum et a1. Apr. 14,1914 Number $085,166 97,890

Nolte June 29, 1937 Name Date Graham June 9, 1925 Beaubien Nov. 7, 1916Wler Dec. 16, 1890 Harte Oct. 9, 1894 Hebern et a1. Feb. 10, 1914Kanschine Sept. 12, 1911 Kurowskl June 25, 1929 FORFHGN PATENTS CountryDate Switzerland 1923

